Method of making tubular insulation



March 18, 1941. w. F. FISCHER METHOD OF MAKING TUBULAR INSULATION Filed July 23, 1956 o D I mill a D l llllImHhn" ihMl l|||||H L L mvENToR BY@ t Ar'roRN'EY Patented Mar. 18, 1941 ifJNlTED STATES 2,235,630 METHOD F MAKING TUBULAR llNSULA TION Wilbur F. Fischer, Somerville, N. J., assigner to .lohns-Manville Corporation, New York, N. Y.,

a corporation of New York Application July 23, 1936, Serial No. 92,099

. 1 Claim.

This invention relates to a method and ma'- chine for winding sheet material into a tube and to the resulting tubular product.

Because the invention is particularly useful in making sectional pipe covering including composited alternating sheets of plane and corrugated surface, respectively, the invention will be illustrated by reference particularly to making such pipe covering. The invention comprises\`the novel features of the machine,A method and product herein described and relatos especially to decreasing thev lack of symmetry in the tubular product and maintaining the corrugations in the product in 5 firm and supporting Contact with the piane sheets adhered over or under the said corrugations.

A preferred embodiment of the invention is illustrated in the attached drawing and will be o described for the purpose of exempliiication in -0 connection therewith.

Fig. l is a side view, partly diagrammatic, of the machine for forming my improved tubular product.

., Fig. 2 is a side view, on a scale somewhat en- "\-larged as compared with the scale of Fig. l, of a portion of the said machine.

Fig. 3 is a perspective view of iinished sectional pipe covering made in accordance with the invention.

Referring to Fig. 1, a suitable source of supply is shown for a cellular material il. This material may be corrugated asbestos paper formed of a sheet oi corrugated paper adhered on one side to a sheet of plane paper. In such paper the corrugations are adapted to be appreciably flattened by being subjected to slight compression, applied to their tops, and to return approximately to their original form after the compression is released. In other words, the corrugations are appreciably resiliently deformable.

The one-ply composite i i may be made in the conventional manner, as by the application ci a fluent hardenable adhesive composition over the tops oi the corrugations of one sheet, pressing the thus coated tops of the corrugatlons against the plane sheet, and hardening the adhesive composition. in the composite so made, the bases of the several corrugations are adhered hrmly to the sheet of plane surface at approximately iixed spacings between the several corrugations.

The composite is then coated on one face thereof with additional fluent hardenable adhesive, as by means of the roller l2 extending at its lower portion into the pan containing the adhesive i3 and at its top portion contacting with the corrugated face of the composite.

The adhesive used in making the one-ply composite or as the said additional adhesive may consist of an aqueous solution of sodium silicate, an aqueous casein adhesive, or a solution of a suitable resin in a. volatile solvent or extender. The hardening is effected at an elevated temperature, to cause evaporation of volatile material and/or polymerization, in case a polymer- 10 izable resin is used.

The thus treated composite then is drawn as illustrated, to the winding machine. During this drawing, the sheet material is subjected to a braking or retarding action, in direction oppo- 15 site that of the said drawing, due to the friction in the various rolls illustrated or otherwise, so that the sheet of plane paper in the composite is ymaintained in taut condition as it is laid upon an underlying turn upon the mandrel. 0 The winding mechanism includes a mandrel I4 and means for rotating the mandrel, as, for example, a manually operated handle i8. The mandrel i6 is supported at one end by a xed bearing and at the opposite end by a bearing 21 25 carried by an arm. i9 hinged at 20 t the frame of the mechanism to enable the bearing 21 to be swung away from the mandrel i4. l A drum or roller l5 is carried by a support which is guided on vertical rods carried by the mechanism frame, and supported on these rods by coil springs i6 interposed between the bottom of the guided support and collars carried by the guide rods. This mounting arrangement causes the roller I5 to be resiliently urged to- 35 wards the mandrel i4. .A treadle I1 is connected by means of a link with the guided support for the roller i5 and enables the roller i5 to be moved away from the mandrel by an operator pressing downwardly upon the treadle i1. 40

it will be understood that an inner liner 24 of plane paper coated with an adhesive may be applied around the mandrel before the winding of the one-ply composite is begun, so that the liner becomes adhered to the composite applied 45 thereover.

it `will be understood, also, that the said retarding action is exerted in direction opposite to that of movement of the sheet material at the time of its being first laid upon an underlying 50 turn of the said material or upon the inner liner. lin the actual winding operation, the one-ply composite, with its corrugated side towards the mandrel is laid with its end edge against the mandrel or against the coated liner of plane paper previously applied thereto. While the edge of the composite is held down firmly, the mandrel is rotated in the direction of the arrow, so that the composite is wound therearound, the operator's hand suitably being held against the outside or plane surface of the composite, as the mandrel is rotated, so that the hand exerts a braking and smoothing eil'ect upon the com-4 posite.

The one-ply composite at the moment of being laid upon the mandrel or upon an .underlying previously formed turn of the said composite is subjected to slight compression directed towards the mandrel by the roller i5.

As a result there may be slight'compression and appreciable flattening of the said corrugations. at the moment that any one of them is being laid upon an underlying element of the tube. 'I'here results a tight assembly. Any slightly 'attened corrugation, once it passes the zone of compression, tends'to return to its original form. When this is the case, there is produced an inner expansion effect, the expanding force being directed outwardly and radially; under the inuence of this force, the plane paper tends to assume the form of turns of the largest possible area of cross section, in proportion to the length of a given turn, namely, turns of approximately regular curvature..as distinguished from the lopslded nature of the turns heretofore produced. When the resulting tube is subjected to treatment to harden the adhesive. as will be described later, there is produced a tube in which the corrugations contact firmly with sheets of plane surface and in which the corrugations may be under radial compression to such degree that there is increased resistance of the tube to deformation by light loading thereof.

When the composite has been wrapped upon itself, to give a tube of approximately the wall thickness desired, the tube is severed from the assenso oncoming compositev l I, as by stopping the rotation of the mandrel and cutting the said composite with a knife at position 25. 'Ihe free end 4thus left integral with the material of the tube is smoothed down and adhered to the tube.

If desired, an outer wrapper 28 of paper of plane surface may be adhered around the tube.

Then. the drum i! is lowered from the operating position, as by the operator pressing upon the treadle l1, and the arm or gate I9, which supports the mandrel bearing 2l at one end, is

swung on the hinge 20, away from the mandrel.

The tube 2i is then slipped from the mandrel, over the end thereof that was formerly supported by the bearing pivotally mounted on arm I 9, and is subjected to drying to harden the additional adhesive supplied by the roller i 2. The tube is then sawed longitudinally at position 22 and scored on the oppositegide, as at 23.

It will be understood that the details given are for the purpose of illustration, not restriction,

and that variations within the spirit of the invention are intended to be included in the scope of the appended claim.

What I claim is:

A method of making pipe covering comprising coating a web of composited plies of plane and corrugated sheets of flexible, thermal-insulating material with an adhesive, tightly wrapping said coated material spirally uponv itself while continuously applying sunlcient pressure against the face of said material near thepoint of initial wrapping to slightly compress the `corrugations of the corrugated sheets and thereby create stress within the material acting to force the convolutions tightly together and into a compact. regularly formed body, and hardening the adhesive while the body is in its stressed condition.

` W'ILBUR F. FISCHER. 

